docs: def writln(line, unit):
      """
      Internal undocumented command for writing a text line to a logical unit
  
      No URL available; relevant lines from SPICE source:
  
      FORTRAN SPICE, writln.f::
  
          C$Procedure      WRITLN ( Write a text line to a logical unit )
                SUBROUTINE WRITLN ( LINE, UNIT )
                CHARACTER*(*)      LINE
                INTEGER            UNIT
  
          C     Variable  I/O  Description
          C     --------  ---  --------------------------------------------------
          C     LINE       I   The line which is to be written to UNIT.
          C     UNIT       I   The Fortran unit number to use for output.
  
      CSPICE, writln.c::
  
          /* $Procedure      WRITLN ( Write a text line to a logical unit ) */
          /* Subroutine */ int writln_(char *line, integer *unit, ftnlen line_len)
  
      :param line: The line which is to be written to UNIT.
      :type line: str
      :param unit: The Fortran unit number to use for output.
      :type unit: int
      """
      lineP    = stypes.stringToCharP(line)
      unit     = ctypes.c_int(unit)
      line_len = ctypes.c_int(len(line))
      libspice.writln_(lineP, ctypes.byref(unit), line_len)